Does your MacBook burn your legs? Does the every running fan give you a headache? Take control of the fans using smcFanControl, an amazing free little utility.
Download and unzip smcFanControl from www.conscius.de. Drop it in the Applications folder. The first time you start it up it will ask you for your user name and password. smcFanControl resides on the right hand side of the menu bar. I recommend checking Autostart smcFanControl after login in the Preferences window.
Cooling Down your Computer:
Open the Preferences window for smcFanControl. Click the + button beside the Favorites pop-down menu to define a new fan speed. Enter a name, Cool, for example and move the slider to somewhere above 3500 rpm. Setting it at the highest speed, 5500 rpm, is not a good idea as it uses more juice and shortens your fan life. It’s a good idea to check Autoapply favorite when power source changes, which allows you to use a lower fan speed when the computer is unplugged to save battery.
Slowing Down the Fan:
Is your fan running non-stop at high speeds even when the computer is cool? smcFanControl does not allow you to set a maximum speed for the fans through the user interface, so let’s head over to Terminal. Paste this line in the command prompt and hit enter;
/Applications/smcFanControl.app/Contents/Resources/smc -k F0Mx -w 60e0
The number 60e0 at the end is 6200 rpm. Change this to the speed of your choice (3e80 is 4000 rpm.), but use common sense: if the max fan speed is too low (under 3000 rpm) you risk over heating your computer. Unfortunately this command has to be run every time you log in. To get around this easily open up Automator. Add Utilities > Run Shell Script to the workflow and paste in the same line above. Save your work flow as an application. Open System Preferences > Accounts > Login Items and add your newly created application to the list. And your good to go!